What is "tremolite"

Amphibole \Am"phi*bole\ ([a^]m"f[i^]*b[=o]l), n. [Gr. 'amfi`bolos doubtful, equivocal, fr. 'amfiba`llein to throw round, to doubt: cf. F. amphibole. Ha["u]y so named the genus from the great variety of color and composition assumed by the mineral.] (Min.) A common mineral embracing many varieties varying in color and in composition. It occurs in monoclinic crystals; also massive, generally with fibrous or columnar structure. The color varies from white to gray, green, brown, and black. It is a silicate of magnesium and calcium, with usually aluminium and iron. Some common varieties are tremolite, actinolite, asbestus, edenite, hornblende (the last name being also used as a general term for the whole species). Amphibole is a constituent of many crystalline rocks, as syenite, diorite, most varieties of trachyte, etc. See Hornblende.

n. (context mineralogy English) A pale grey/green amphibole mineral that is a mixed calcium and magnesium silicate, with the chemical formula calcium₂magnesium₅silicon₈oxygen₂₂(Ohydrogen)₂; sometimes used in place of asbestos.

n. a white or pale green mineral (calcium magnesium silicate) of the amphibole group used as a form of asbestos

Tremolite is a member of the amphibole group of silicate minerals with composition: ☐Ca(MgFe)SiO(OH). Tremolite forms by metamorphism of sediments rich in dolomite and quartz. Tremolite forms a series with actinolite and ferro-actinolite. Pure magnesium tremolite is creamy white, but the color grades to dark green with increasing iron content. It has a hardness on Mohs scale of 5 to 6. Nephrite, one of the two minerals of the gemstone jade, is a green variety of tremolite.

The fibrous form of tremolite is one of the six recognised types of asbestos. This material is toxic and inhaling the fibers can lead to asbestosis, lung cancer and both pleural and peritoneal mesothelioma. Fibrous tremolite is sometimes found as a contaminant in vermiculite, chrysotile (itself a type of asbestos) and talc.